Fixing Loose Tuners
Normal playing as well as fluctuations in humidity can cause parts on your tuning machines to loosen up over time. Loose bushing washers can rattle when you play, and loose buttons can eventually fall off and be lost, making tuning impossible. Inspecting your tuning machines is not only an important part of regular maintenance, but it may just solve that mystery buzz or rattle you’ve been wondering about. The following procedure is best performed with the strings off, because it makes finding loose tuner problems more obvious.
First, check the bushings and washers with a nut driver (usually 10 mm) or small adjustable wrench to make sure they are snug but not too tight. If you have vintage-style press-in bushings, make sure they are seated all the way down against the peghead. Now let’s move to the buttons—if they are glued on you can skip this step. Some players overtighten the tuner button screws, believing this will help keep their guitar in tune. But this can actually pinch the little plastic washer between the button and the shaft, causing it to break. The button screws should be snug but not so tight that the gears are hard to turn. If your guitar has wood buttons, and one just spins without raising the pitch of the string, the metal insert in the button may have stripped. To fix this, remove the button from the gear. Use a drop of thin superglue to affix the outside of the insert to the inside of the button hole, but try not to get any glue down inside the insert. If you have open vintage-style or classical gears, a drop of three-in-one or Tri-Flow oil where the worm and gear meet will help keep them running smooth and prevent unnecessary wear.
Excerpted from Acoustic Guitar July 2013